On other platforms:

FREE

FREE

App description:

GameChanger app let's you use your mobile device to send plays to your on field players. You enter your play into the app and press the button next to the play, then it lights the LED next to the play on the player's wristband. It will also allow you to press vibrate, so you can go on a silent count in noisy situations. All on field players will receive the signal (as many as you would like).